AMIVfAL CHEMISTRY. 



cal action" signifies neither more nor less 

 than the act of change in them ; that these 

 effects depend on the presence of a conduc- 

 tor, of a substance which propagates in all 

 directions, where it is not neutralized by re- 

 sistance, the force or momentum produced ; 

 that this force becomes a momentum of 

 motion, by means of which we can produce 

 mechanical effects, and which, when trans- 

 ferred to other bodies, communicates to 

 them all those properties, the ultimate cause 

 of which is the chemical force itself; for 

 these bodies acquire the power of causing 

 decompositions and combinations, such as, 

 without a supply of force through the con- 

 ductor, they could not effect. 



If we employ these well known facts as 

 means to assist us in investigating the ulti- 

 mate cause of the mechanical effects in the 

 animal organism, observation teaches us, 

 that the motion of the blood and of the other 

 animal fluids proceeds from distinct organs 

 which, as in the case of the heart and in- 

 testines, do not generate the moving power 

 in themselves, but receive it from other 

 quarters. 



We know with certainty that the nerves 

 are the conductors and propagators of me- 

 chanical effects; we know, that by means of 

 them motion is propagated in all directions. 

 For each motion we recognize a separate 

 nerve, a peculiar conductor, with the con- 

 ducting power of which, or with its inter- 

 ruption, the propagation of motion is affected 

 or destroyed. 



By means of the nerves all parts of the 

 body, all the limbs, receive the moving force 

 which is indispensable to their functions, to 

 change of place, to the production of me- 

 chanical effects. Where nerves are not 

 found, motion does not occur. The excess 

 of force generated in one place is conducted 

 to other parts by the nerves. The force 

 which one organ cannot produce in itself is 

 conveyed to it from other quarters ; and the 

 vital force which is wanting to it, in order 

 to furnish resistance to external causes of 

 disturbance, it receives in the form of excess 

 from another organ, an excess which that 

 organ cannot consume in itself. 



We observe further, that the voluntary 

 and involuntary motions, in other words, all 

 mechanical effects in the animal organism, 

 are accompanied by, nay, are dependent on, 

 a peculiar change of form and structure in 

 the substance of certain living parts, the in- 

 crease or diminution of which change stands 

 in the very closest relation to the measure of 

 motion, or the amount of force consumed 

 in the motions performed. 



As an immediate effect of the manifesta- 

 tion of mechanical force, we see, that a part 

 of the muscular substance loses its vital 

 properties, its character of life; that this 

 portion separates from the living part, and 

 loses its capacity of growth and its power of 

 resistance. We find that this change of 

 properties is accompanied by the entrance 

 of a foreign body (oxygen) into the composi- 



tion of the muscular fibre (just as tne acid 

 lost its chemical character by combining 

 j with zinc ;) and all experience proves, that 

 I this conversion of living muscular fibre into 

 compounds destitute of vitality is accelerated 

 or retarded according to the amount offeree 

 employed to produce motion. Nay, it may 

 safely be affirmed, that they are mutually 

 proportional ; that a rapid transformation of 

 muscular fibre, or, as it may be called, a 

 rapid change of matter, determines a greater 

 I amount of mechanical force ; and con- 

 j versely, that a greater amount of me- 

 I chanical motion (of mechanical force ex- 

 pended in motion) determines a more rapid 

 change of matter. 



Prom this decided relation between the 

 change of matter in the animal body and the 

 force consumed in mechanical motion, no 

 other conclusion can be drawn but this, that 

 the active or available vital force in certain 

 living parts is the cause of the mechanical 

 phenomena in the animal organism. 



The moving force certainly proceed? from 

 living parts; these parts possessed a mo- 

 mentum of force or of motion, which they 

 lost in proportion as other parts acquired 

 a momentum of force or of motion; they 

 lose their capacity of growth, and their 

 power to resist external causes of change. 

 It is obvious that the ultimate cause, the 

 vital force, from which they acquired these 

 properties, has served for the production of 

 mechanical force, that is, has been expended 

 in the shape of motion. 



How, indeed, could we conceive that a 

 living part should lose the condition of life, 

 should become incapable of resisting the 

 action of the oxygen conveyed to it by the 

 arterial blood, and should be deprived of the 

 power to overcome chemical resistance, 

 unless the momentum of the vital force, 

 which had given to it all these properties, 

 had been expended for other purposes 1 



By the power of the conductors, the 

 nerves to propagate the momentum of force 

 in a living part, or the effect which the 

 active vital force inherent in the part pro, 

 duces on all the surrounding parts, in all 

 directions where the force, or rather its mo- 

 mentum of motion, is consumed without 

 resistance, (for without motion no change 

 of matter occurs, and when motion has 

 begun, there is no longer resistance,) an 

 equilibrium is obviously established in the 

 living part, between the chemical forces and 

 the remaining vital force ; which equilibrium 

 would not have occurred had not vital 

 force been expended in producing me- 

 chanical motion. 



In this state, any external cause capable 

 of exerting an influence on the form, struc- 

 ture and composition of the organ meets 

 with no further resistance. If oxygen were 

 not conveyed to it, the organ would main- 

 tain its condition, but without any mani- 

 festation of vitality. It is only with the 

 commencement of chemical action that the 

 change of matter, that is, the separation of 



